Differential treatment of multilayer films



Patented Nov. 3, 1936 PATENT OFFICE 2,059,887 nmrnnasrmr. 'rasarrms'r or m'rrmvna rmms Leopold D. Mannesand Leopold Godowsky, Jr.,

Rochester, N. Y., assignors, by mesne assignments, to Eastman Kodak Company, Jersey City, N. J., a corporation of New Jersey No Drawing. ApplicationFebruary 27, 1935, Serial No. 8,517

24 Claims.

This invention relates to photography and more particularly to difierential treatment of the layers of a multi-layer film.

This application is a. continuation in part oi. our application Serial No. 634,182, filed September 21, 1932. It is also related to the subject matter of our Patent No. 1,997,493 granted April 9, 1935 and application Serial No. 645,514, filed December 3, 1932.

In processing photographic films having several layers or strata of sensitized material coated on a support, it is often desirable to subject the strata to a difierential treatment in which less than all of the strata are treated. Such a process is disclosed in our prior Patent No. 1,954,452, I

April 10, 1934. The strata thus treated are very thinand it is, therefore, necessary to control the penetration of the bath with extreme accuracy. It has been proposed to treat the film with a retardant prior to treatment with a processing bath and it has also been proposed to control the time of treatment in the bath. These methods, however, have numerous disadvantages.

The principal object of the present invention is to provide methods and means for controlling the penetration and diifusion of a processing bath for multi-layer films whereby it will be limited in its action to the outer layer or layers or image or images. A further object is to produce .color developers and other processing baths of controllable action whereby their penetration into the film may be. accurately limited and controlled.

The various means by which we control and limit the penetration -ofsuch a processing bath are: t

1. The diffusion of the bath into the layer is retarded by inert substances added to the bath;

2. The action of the processing bath israpidly interrupted orterminated by means of a stop bath;

3. The layer. is in a thoroughly dry condition when the processing bath is applied;

4. The several layers of the film are separated by inert layers;

5. The temperature of the photographic element. is suddenly and materially lowered; This step is more eifectivc with certain baths than useful independently, are of greatest utility when used together, although all do not need to'be used since certain of the steps are particularly (ores-2i useful in combination with certain other control means. The'last mentioned two methods are of definitely minor importance.

Preferably the photographic material used is one in which two or three layers of differentially 5 color sensitized material are coated one upon another with intervening layers of inert material.

- Ordinarily gelatine is the material of all the layers and all have the same permeability so that, unless otherwise controlled, the baths have the 10 same diffusing properties as to all the layers.

Our method may be applied to processes such as those disclosed in our Patent No. 1,516,824, granted November 25, 1924, our prior application, Serial No. 634,182, filed September 21, 1932, 15 or our application, Serial No. 8,516 filed February 27, 1935. Our invention includes the use of retardants in all kinds of photographic baths, such as dye-forming, bleaching, developing, toning, and fixing baths and to means for controlling 20 and terminating the action of such baths.

The materials which we add to these baths in order to retard penetration of the bath may be of two general types which we believe to act as follows: The first type acts by causing a re- 5 pellency between gelatin and the material added, a material of this type being alcohol. The second type acts by increasing the viscosity of the treatment bath, a material of this type being sodium sulfate. These two types of retardants 3o possess the common property of dehydrating the gelatin or of producing an anti-swelling efiect.

The stop bath material is, in general, any material which will quickly neutralize or counteract the action of the bath immediately'preced- 5 ing it.

Our invention is more clearly illustrated by the following examples of treatment baths capable of chemically transforming a photographic image, in which a retardant is added to the bath. 4o Thefollowing formula illustrates a bleach bath 7 which may be used to decolorize a dye in various types of multi-layer films, methyl alcohol, sugar and salt being used as the retardants:

In using this bleach bath, B is added to A.

A stop bath suitable for terminating the action 55 of this bleach bath comprises a 2% solution of sodium bicarbonate in water. The film is treated in this bath immediately after being removed from the bleach bath and the bleaching action is thereby terminated.

In the process disclosed in our prior application Serial No. 634,182, the images in the individual layers of a multi-layer film are colored by a dyeforming development which acts on silver ferricyanide to convert it to metallic silver and form a dye. In order to decolorize and recolor the image in the outer layer the colored image is bleached in a bath which destroys the dye and re-converts the silver to a silver salt. A bath suitable for this purpose is the following:

Formula II-R Chromic acid, 10% solution cc 10 Hydrobromic acid, 41% solution cc 3 Potassium bromide "grams..- 2 Methyl alcohol cc 300 Water cc 90 A stop bath suitable for terminating the action of this bleach bath is the following:

F0rmu1aII-S Ammonia, 28% cc 5 Water" cc 1000 Our application, Serial No. 634,182 also discloses bleaching the silver images in a potassium ferricyanide bath which converts the silver to silver ferrocyanide. This bath contains sodium sulfate which acts as a retardant.

Formula III-R Potassium ferricyanide grams Sodium sulfate grams 200 Water to liter. 1

The bleach action of this bath is arrested by immediately immersing the film in a vdilute solution of hydroxyl-amine hydro-chloride and ammonia which converts the remaining ferricyanide to potassium ferrocyanide, the latter having no bleaching action. This bath may have the following formula:

Formula III-S Hydrorwbamine hydrochloride grams 20 Ammonia, 28% cc 50 Water to 1 developer solution. This process may be applied to reversed images or the film may be developed as a negative, and positives printed from it.

As applied to reversal processes, the essential steps involved in the process are as follows: The film containing the negative image is developed in an ordinary metol-hydroquinone type of developer, bleached to remove the silver images thereby formed, and exposed to light to develop the complementary silver bromide images. The

film is then immersed in a color-forming developer and monochrome-dye images formed in each of the layers. The film is then fixed to remove any residual silver halide which may be present, and dried. The next step, which is a critical one in the process, involves bleaching the outer layer or layers but not the innermost layer to decolorize the dye and convert the silver in the outer layer or layers to silver halide. A retardant is used in this bleach bath to control the depth and time of penetration of the bath. The drying step referred to above is also important in controlling the penetration of the bleach bath. In order to terminate the action of this bleach bath at the desired time the film is then immediately immersed in a stop bath which in the case of an acid bleach bath may be a mild alkali such as sodium bicarbonate. The outer emulsion layer or in the case of a three-layer film the two outer layers are then redeveloped by immersion in a color-forming developer which forms dye images of another color in those layers by development of the silverhalide and formation of a dye at the image portions. The outer layer is then bleached as before in a bleach bath containing a retardant and the film again immediately subjected to a stop bath such as sodium bicarbonate or sodium bisulfite. The outer layer is then finally colordeveloped to a third color and the silver in the images removed from the three layers. The bleach baths used to decolorize the dye and convert the silver to silver halide in this process may have one of the following formulae in which isopropyl alcohol, glycerine or ethylene glycol act as the retardants:

Formula IV'R A stop bath suitable for terminating the action of each of these bleach baths may have the following formula in which sodium bicarbonate acts as the stopping or terminating agent, the bath also containing iso-propyl alcohol and glycerine:

Formula VI--S sodium bicarbonate grams-.. 15 Iso-propyl alcohol cc 1000 Glycerine l cc 1000 Water cc 1000 Our invention may also be applied to developer baths. In a modification of the process disclosed in our prior application, Serial No. 034,182, the multi-layer film containing color separation latent images is subjected to a differential development. The outer image only is developed and the image in the inner layer is then colored by a color development procedure. Developers suitable for this differential development are the following:

Formula VII-R Hydroquinone "grams-.. 12.5 Sodium sulflte grams 19.0 KOH -grams 41.0 Nazsol "grams" 200.0 Water to liter 1 Formula VIII-R Amidn'l rams-.. 50 Sodium sulflte "grams" 100 NaaSO: grams" 200 Water to li er" 1 A suitable stop bath for terminating the action of these developer baths may have the following formula:

Formula VII- -S Sodium bisulflte grams.... 50 Glacial acetic acid .cc 30 Water to li er... 1

The following stop bath may be used with these developer baths .as an alternative formula;

Formula VIII-S Glacial acetic acid cc-- 50 Water ..liter 1 Each of these stop baths should be cooled to a temperature of C. to C. for use. Hydroquinone and its derivatives are very sensitive to temperature and are relatively inactive at low temperatures. For this reason the use of these stop baths at a low temperature brings about an immediate cessation of the developing action.

A 3% acetic-acid solution may also'be used as a stop bath for these developers.

Retardants are also added to the developer bath used with the dye-forming color developers which we have described above in connection with the process of our copending application, Serial No. 8,516. Such a developer bath is the following: Formula lX-R I Z-amino 5-diethyl amino toluene H01 As examples of the retardants which we may employ, various compounds may be mentioned. Among the organic solvents the alcohols have been found suitable. These include the primary, secondary and tertiary forms such as methyl alcohol, normal propyl, iso-propyl, the butyl alcohols and amyl alcohol. The ketones may be used,

such as acetone and its homologues. Amines may be used, such as methyl, ethyl and propyl, and higher amines; tri-ethanol amine and other alkyl amines; acetylated alkyl amines such as nitrogen methyl acetamide, and acetamide. Among the viscous compounds which may be used are-glycerol; the glycois such as ethylene and 'propylene glycol, dihydrox'yethylether, or solu- "tions of gelatin, gum arable, etc. in water; and solutions of various solids such as sugar, sodium sulfate and sodium chloride. 2

These compounds may be used alone or two or more may be used together as retardants. Va

rious proportions may be used depending on the degree of retarding action desired. It has been found that a dye bleaching bath, for example, which penetrates a gelatin layer of .0005 inch thickness in one or two seconds can be so retarded that it will penetrate the same thickness of gelatin in four or five minutes by the addition of 75% of a retardant to the solution. The time of penetration may be decreased or increased as desired by the addition of more or less of retardant.

' The stop baths which may be used include as the active ingredient any agent which will hinder or terminate the action of the bath immediately preceding it. Such agents may be those which perform a chemical function, opposing that of the prior bath or which react with an ingredient of the prior bath to nullify its action. An acid stop bath may be used to terminate the action of an alkaline bath preceding it or an alkaline stop bath may be used to terminate the use of a preceding acid bath. An alkaline stop bath material is, for example, an ammonia solution, and various neutral, alkaline, or weakly acid solutions may be used such as sodium bisulflte, potassium meta-bisuliite, sodium sulflte, sodium bicarbonate, mono or di-basic sodium phosphates and sodium acetate. Reducing agents may be used to terminate the action of an oxidizing bath or oxiused, it includes any chemical or physical action" 40 whereby the substance of the image is changed from one substance to another, such as from a silver salt to silver, the addition of a substance to the previous substance of the image as in the dye toning of a metallic salt image or the removal of part of the material of the image such as either silver or dye from a combined silver and dye image.

It is to be noted that in each of the examples.

given above the rate of diffusion of the. stop bath through an unhardened gelatin emulsion is more rapid than that of the developing, bleaching or toning bath, theoperation of which it terminates.

It is to be understood that we consider as included within our invention all modifications and equivalents included within the scope of the appended claims. 7

What we claim as new and desire to secure by Letters Patent in the United States is:

'1. A process for treating a photographic element having photographic images in different layers on one side of a support that comprises submitting the element to a bath which is capable of diffusing into all of the layers and of transforming the images therein, said bath including a substantially inert material tending to retard the diilusing of said bath, until at least one of the outer images is substantially completely transformed and then discontinuing the action of such bath beforean inner image is aifected.

2. A process for treating a photographic element having photographic images in diilerent layers on one side of a support that comprises submitting the element to a bath which is capable of diffusing into all of the layers and of chemically transforming the images therein, said bath including an oxidizing agent and a viscous liquid, until at least one of the outer images is substantially completely transformed and then discontinuing the action of such bath before an inner image is affected 3. A process for treating a photographic element having photographic images in different layers on one side of a support that comprises submitting the element to a bath which is capable of diffusing into all of the layers and of chemically transforming the images therein, said bath including an oxidizing agent, a viscous liquid, and an acid, until at least one of the outer images is substantially completely transformed and then discontinuing the action of such bath before an inner image is aifected.

4. A process for treating a photographic element having photographic images in different layers on one side of a support that comprises submitting the element to a bath which is capable of diffusing into all of the layers and of chemically transforming the images therein, said bath including an oxidizing agent and an alcohol, until at least one of the outer images is substantially completely transformed and then discontinuing the action of such bath before an inner image is affected.

5. A process for treating a photographic element having photographic images of similar physical structure in different strata thereof that comprises submitting the element to a bath that is capable of difi'using into both strata and of chemically transforming the images thereon, said bath including a substantially inert material tending to retard the difiusing of said bath, until the outermost image is substantially completely transformed and then discontinuing the action of such bath before an inner image is affected.

6. A process for treating a photographic element having photographic images of similar physical structure in different strata thereof that comprises submitting the element to a bath which is capable of diifusing into both strata and of chemically transforming the images thereon, said bath including an oxidizing agent and an alcohol tending to retard the diffusing of said bath, until the outermost image is substantially completely transformed and then discontinuing the action of such bath before aninner image is affected.

7. The method of treating differentially two photographic strata lying one upon another upon the same side of a common support that comprises submitting the photographic element to a processing bath capable of diffusing into both strata and of acting on both images therein, said bath including a substantially inert .material tending to retard the diffusing of said bath, until the outermost image is substantially completely acted upon thereby and the inner image is not substantially affected, and then at once submitting it to a treatment that immediately arrests thereof that comprises submitting it to a developing bath including sodium sulfate in an amount .which retards the rate of diffusion of the bath and discontinuing the action of the developer when it has developed an image in the upper part of the layer and before it has developed an image in the lower part of the layer.

10. The method of developing a photographic layer containing latent images in different strata thereof that comprises submitting it to a developing bath including an alcohol in an amount which retards the rate of difiu'sion of the bath and discontinuing the action of the developer when it has developed an image in the upper part of the layer and before it has developed an image in the lower part of the layer.

11. The method of treating a photographic film having a plurality of emulsion layers on the same side of a support and containing silver images representing different color components which comprises submitting said film to a bath capable of transforming silver into a silver salt, until at least one of the upper images is transformed but the lowermost image is not materially affected, and then at once submitting the film to a bath containing sodium bicarbonate.

12. The method of treating a photographic film having a plurality of emulsion layers on the same side of a support and containing metallic silver and dye images representing difierent color components which comprises submitting said film to a bath capable of transforming metallic silver into silver salt and decolorizing the dye, until at least one of the upper images is transformed, but the lowermost image is not materially affected, and then at once submitting the film to a bath that immediately stops the action of the first bath.

13. The method of treating. a photographic film having a plurality of emulsion layers on the same side of a support and containing silver and dye images representing different color components which comprises submitting said film to a bath capable of transforming silver into silver salt and decolorizing the dye, until at least one of the upper images is transformed, but the lowermost image is not materially affected, and then at once submitting the film to a bath containing sodium bicarbonate.

14. In a method of processing a photographic layer having images in different strata, the steps of bleaching one of said images by submitting the layer first to a solution comprising potassium ferricyanide and then, before the first solution has acted on the lower stratum, to a solution containing hydrazine.

15. In a method of processing a photographic layer having images in different strata, the steps of bleaching one of said images by submitting the layer first to a solution comprising potassium ferricyanide and then, before the first solution has acted on the lower stratum, to a solution containing hydroxyl-amine hydrochloride.

16. The step of terminating the action of a bleaching bath containing a chromium oxidizing agent and a soluble halide which comprises immersing in an alkaline solution a photographic element which has been subjected to the bleaching bath.

17. The step of terminating the action of a bleaching bath containing chromic acid, hydrobromic acid and potassium bromide which comprises immersing in a solution containing an alkali sulphite and ammonia a photographic film which has been subjected to the bleaching bath.

18. A solution for terminating the action of a ferricyanide bleaching bath that comprises alkaline hydrazine.

19. A SOI'ltlOIl for terminating the action of a ferricyanide bleaching bath which comprises hydroxylamine and alkali.

20. A process for differentially treating a photographic element having sensitive material in layer form in one side of a support that.c om prises forming latent images in difierent strata of said material, submitting the images to a photographic treatment that transforms them into visible images, drying the element, submitting the element to a bath capable of affecting both images until it has affected the outer image only and then at once submitting it to a bath that immediately arrests the action of the first named bath.

21. A process for differentially treating a photographic element having photographic latent.

images in different strata on the same side of a support that comprises transforming the latent images into images of the same physical nature, drying the element and then submitting the element to a bath capable of diffusing into the strata and affecting the images therein and in- 22. In a process for diiierentially treating a.

photographic element having photographic images in different strata thereof that comprises submitting the element to a bath that diffuses into the layer and affects the images therein, the step of'controlling the diffusion of such bath into the layer by suddenly submitting it to a low temperature.

.23. In a process for differentially treating a photographic element having photographic images in different strata thereof that comprises submitting the element to a bath that diifuses into the layer and.- aifects the-images therein, the method of controlling the diffusion of such bath that comprises including therein a substantially inert material and suddenly submitting it to a low temperature.

24. The method for differentially treating a photographic element having photographic images in difierent strata thereof that comprises submitting the element to a developer for a determined time, wherein development will have proceeded to a definite depth, submitting the element to an acid stop at a low temperature, thereby arresting the action of the developer.

LEOPOLD D. MANNES. LEOPOLD GODOWSKY, JR. 

